Evidence exists to suggest that oral manifestations are markers of HIV- disease progression in children and may have the potential for prognostic value independent of other commonly used markers such as CD4 counts. In addition, the oral manifestations of HIV infection in children are different from those found in adults. For these reasons, it is important to study the oral manifestations of HIV infection in children. Several important observations on the oral manifestations of HIV infection in children were made during the preliminary studies of the Phase 1 funding period of the NMOHRC, including: 1-confirmation of the high levels of dental caries, pain and other soft tissue pathology; 2-documentation of a high level of untreated oral disease and poor compliance with recommendations for oral health care; 3-confirmation of previous reports of high levels of putative pathogens in the microflora of pediatric HIV infected patients; 4- the dissociation of bacterial colonization with clinical evidence of disease; and, 5- the observation of moderate levels of periodontopathic bacteria in the oral cavity of HIV negative coinhabitants of pediatric HIV infected patients. These observations are the basis for studies and interventions planned for the next 5 years of the NM0HRC. These studies will achieve the following Specific Aims: 1-To determine the risk factors for increased dental caries in HIV positive children compared to HIV negative children; 2-To investigate factors which may be associated with poor compliance with dental care recommendations for HlV infected children; 3- To determine the prevalence of gingivitis, periodontal disease, oral candidiasis, infection with selected periodontal pathogens, pain and other oral pathology in HIV infected children and HIV negative siblings; and 4- To correlate relevant blood laboratory values, clinical status and medications in the HIV positive subjects with clinical observations related to dental caries, gingivitis, periodontal disease and other oral pathology. The goals of these studies are to better understand the etiology, prevention, treatment and prognostic value of the oral manifestations of HIV infection in children.